1. Field of the Invention
This invention relates generally to bending tools for installing and assembling heating and ventilating system ducts and more particularly to a tool for joining a tap duct, or feeding duct, to a main duct.
2. Description of the Prior Art
In the installation of ducts for heating and ventilating systems, a number of tap ducts are required to feed individual rooms. These tap ducts, which are attached to a main duct, are substantially smaller in cross sectional area than the main duct. The common method of installation is to cut an opening in the main duct wall, insert the tap duct therein, and peen over the duct flange material which extends into the interior of the main duct. Generally a workman may insert a hammer therein to peen over the attached flange material. This is not a simple task and the time involved to peen over these individual units is quite substantial when a number of such installations must be made.
Various duct clenching or crimping devices and tools have been provided in the prior art. In particular, the hand crimper of U.S. Pat. No. 2,572,738 and the crimpers of U.S. Pat. Nos. 3,330,147 and 3,570,299. These crimping tools have not been entirely satisfactory, as evidenced by the lack of acceptance by those in the business of installing and assembling heating and ventilating systems. One reason for their lack of acceptance may be the fact that each of these hand crimpers require clenching a fist around the levers of the tool much like the action involved in the closing of a pair of pliers. This action can become very tiring to the operator upon extended use of the tool.
It is therefore an object of the applicant's invention to provide a duct crimping tool wherein the crimping mechanism requires pushing a handle perpendicularly against the orifice of the tap duct. Use of such force is intended to prevent excessive tiring of the worker installing such tap ducts. This object together with various ancillary objects and features of the invention which will later become apparent as the following description proceeds, are attained by the inventive tap duct crimping tool disclosed herein, a preferred embodiment of which has been illustrated by way of example only in the accompanying drawings.